EP0311396B1 - Appareil d'ancrage et méthode d'installation pour une plate-forme à jambes de tension utilisable en eaux profondes - Google Patents

Appareil d'ancrage et méthode d'installation pour une plate-forme à jambes de tension utilisable en eaux profondes Download PDF

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EP0311396B1
EP0311396B1 EP88309317A EP88309317A EP0311396B1 EP 0311396 B1 EP0311396 B1 EP 0311396B1 EP 88309317 A EP88309317 A EP 88309317A EP 88309317 A EP88309317 A EP 88309317A EP 0311396 B1 EP0311396 B1 EP 0311396B1
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Prior art keywords
tendon
tendons
mooring
water
anchoring means
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EP88309317A
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German (de)
English (en)
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EP0311396A1 (fr
Inventor
Andrew F. Hunter
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ConocoPhillips Co
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Conoco Inc
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Priority claimed from US07/105,941 external-priority patent/US4784529A/en
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
    • B63B21/502—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers by means of tension legs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
    • B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
    • B63B1/10—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls
    • B63B1/107—Semi-submersibles; Small waterline area multiple hull vessels and the like, e.g. SWATH
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
    • B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
    • B63B1/10—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls
    • B63B1/12—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls the hulls being interconnected rigidly
    • B63B2001/128—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls the hulls being interconnected rigidly comprising underwater connectors between the hulls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
    • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
    • B63B2021/505—Methods for installation or mooring of floating offshore platforms on site

Definitions

  • This invention relates to the art of offshore structures and, more particularly, to a tension leg-moored floating structure for exploitation of hydrocarbon reserves located in deep water.
  • a TLP comprises a semi-submersible-type floating platform anchored to piled foundations on the sea bed through substantially vertical members or mooring lines called tension legs.
  • the tension legs are maintained in tension at all times by ensuring that the buoyancy of the TLP exceeds its operating weight under all environmental conditions.
  • the TLP is compliantly restrained by this mooring system against lateral offset allowing limited surge, sway and yaw. Motions in the vertical direction of heave, pitch and roll and stiffly restrained by the tension legs.
  • Prior TLP designs have used heavy-walled, steel tubulars for the mooring elements.
  • These mooring elements generally comprise a plurality of interconnected short lengths of heavy-walled tubing which are assembled section by section within the corner columns of the TLP and, thus lengthened, gradually extend through the depth of the water to a bottom-founded anchoring structure.
  • These tension legs constitute a significant weight with respect to the floating platform, a weight which must be overcome by the buoyancy of the floating structure.
  • the world's first, and to date only, commercial tension leg platform installed in the U.K. North Sea utilizes a plurality of tubular joints thirty feet in length having a ten-inch outer diameter and a three inch longitudinal bore.
  • the tension legs assembled from these joints have a weight in water of about two hundred pounds per foot. In the 485-foot depth of water in which this platform is installed, the large weight of sixteen such tendons must be overcome by the buoyancy of the floating structure. It should be readily apparent that, with increasingly long mooring elements being required for a tension leg platform in deeper water, a floating structure having the necessary buoyancy to overcome these extreme weights must ultimately be so large as to be uneconomic. Further, the handling equipment for installing and retrieving the long, heavy tension legs adds large amounts of weight, expense and complexity to the tension leg platform system. Flotation systems can be attached to the legs but their long-term reliability is questionable. Furthermore, added buoyancy causes an increase in the hydrodynamic forces on the leg structure.
  • a one-piece prefabricated tendon for mooring a tension leg platform to the ocean floor in water depths of up to 3000 feet, said tendon being characterized by: an upper tubular coupling section having a first wall thickness and a first outer tubular diameter; a central tubular section which extends over a substantial majority of the length of said tendon, said central tubular section having a second wall thickness thinner than the first wall thickness and a second outer tubular diameter, larger than the first outer tubular diameter said second wall section having sufficient tensile strength to withstand compressive forces imposed by said ocean; a lower tubular coupling section having a third wall thickness thicker than the second wall thickness and a third outer tubular diameter smaller than the second outer tubular diameter; each of said upper, central and lower tubular sections being comprised of a plurality of segments that are welded into a unitary tendon; and buoyancy means integrated into said one-piece tendon such that said tendon is, at least, substantially neutrally buoyant.
  • the invention extends to a method of mooring an offshore platform in a body of water having a surface and a floor comprising the steps of: providing a plurality of one piece, substantially ridgid tendons according to the first aspect of the invention, locating a plurality of anchoring means on the floor of the body of water, the anchoring means being adapted for receipt of the mooring tendons through a side entry opening therein: stationing a semi-submersible floating structure on the surface of the body of water above said anchoring means, said floating structure including a plurality of external tendon receptacles adapted for side entry receipt of said plurality of mooring tendons, said tendon receptacles being located at an initial distance above said anchoring means; disposing said tendons substantially horizontally near said surface and adjacent said floating structure, said tendons having enlarged top and bottom end connectors and an actual length which is greater than said initial distance; swinging the enlarged bottom end connector of one of said tendons downwardly into a position adjacent one of said plurality of anchor
  • a method of mooring an offshore platform in a body of water comprises locating a plurality of anchoring means on the floor of the body of water, the anchoring means being adapted for receipt of a mooring tendon through a side-entry opening in an anchoring means.
  • a semi-submersible floating structure is stationed above the anchoring means, the floating structure including a plurality of tension receptacles adapted for side-entry receipt of a mooring tendon.
  • the mooring tendons each comprise substantially rigid, one-piece mooring elements which are initially disposed substantially horizontally near the surface and adjacent to the floating structure, the tendons having enlarged top and bottom end connectors and a length which is greater than an initial distance from the tendon receptacles on the floating structure and those on the anchoring means.
  • the enlarged bottom end connector of a tendon is swung downwardly into position adjacent one of the plurality of anchoring means and the enlarged bottom end of the tendon is then pulled through the side-entry opening. The tendon is then lifted to bring the enlarged bottom end connector into contact with a load ring in the bottom receptacle.
  • the enlarged top end connector is also positioned in one of the side-entry tendon receptacles on the floating structure.
  • the effective length of the tendon is then adjusted so that it is equal to or, preferably less than the initial distance, the process being repeated for each of the plurality of tendons and tendon receptacles until the offshore platform is moored in the body of water.
  • the side-entry receptacles for the one-piece tendon incorporate a load-bearing ring which, in installed position, compressively engages the enlarged top and bottom end, connectors respectively, of the one piece tendon structure.
  • the top tendon receptacles are located in an easily accessible position on the exterior surface of the corner columns of the floating structure.
  • the enlarged top and bottom end connectors of the one-piece tendon structure each incorporate a spherical flex bearing which allows for angular deviation of the installed tendons from the vertical position.
  • the one-piece tendons are constructed by welding a plurality of tubular joints together to form a unitary tendon, the assembly of the one-piece tendons taking place at a location remote from the installation site, the one-piece tendons being transported through the water by a buoyant, off-bottom tow method, or surface tow method, depending on water depth and transportation route conditions.
  • the side-entry receptacle on the subsea anchor has a frustoconical first portion with a side-entry opening having a height that is at least twice the height of the maximum height of the connector it receives to facilitate connection thereof.
  • the floating structure 28 generally comprises a number of vertical cylindrical columns 30 which are interconnected below the surface 24 by a plurality of horizontally disposed pontoons 32.
  • the floating structure 28 comprises four cylindrical columns 30 interconnected by four equal-length pontoons 32 in a substantially square configuration when seen in plain view. It will be understood that other configurations are possible including variations of the shapes of the pontoons and the columns and that the number of columns may range from three to eight or more without departing from the general concept of a semi-submersible structure suitable for use as a tension leg platform.
  • a deck structure 34 is positioned on, and spans the tops of, the vertical cylindrical columns 30 and may comprise a plurality of deck levels as required for supporting the desired equipment such as hydrocarbon production well heads, riser handling equipment, drilling and/or workover equipment, crew accommodations, helipad and the like, according to the needs of the particular installation contemplated.
  • a foundation template 36 is located on the floor 26 of the body of water 22 and positioned by a plurality of anchor pilings 38 received in piling guides 39 and extending into the subsea terrain 40 below the sea floor 26.
  • the foundation template includes a plurality of side-entry tendon receptacles 42 located on the corners of the template 36 and positioned intermittently with pile guides 39.
  • the template 36 may include additional features such as well slots for drilling and production of subsea hydrocarbons, integral subsea storage tanks and the like.
  • the semi-submersible floating structure 28 is moored over the foundation template 36 by a plurality of tension legs 44 extending from the corners of the floating structure 28 to the corners of the foundation template 36.
  • Each of the tension legs 44 comprises a mooring tendon 46 which is attached at its upper end to a side-entry tendon tie-down or mooring porch 48 located on the exterior surface of the vertical cylindrical columns 30 of the floating structure 28 and connected at its lower end in one of the side-entry tendon receptacles 42 located on the foundation template 36.
  • the mooring tendons 46 comprise a one piece, thin-walled tubular central section 50 (Fig. 9) with smaller diameter, thick-walled upper and lower tendon coupling sections 52, 54 respectively interconnected with the central section 50 by upper and lower tapered sections 56, 58, respectively.
  • the upper tendon coupling section 52 includes an enlarged upper flex connector 60 which may be adjustably positioned along the length of the upper tendon coupling section 52 such as by screw threads or other adjustment means all of which will be more fully described hereinafter. In this manner, the effective length of tendon 46 can be adjusted.
  • the lower tendon coupling section 54 includes an enlarged lower flex connector 62 in a fixed location at the lower end of the lower tendon coupling section 54 and will similarly be more fully described hereinafter.
  • FIG. 2A through 2F illustrates the installation of a single mooring tendon in accordance with an embodiment of the present invention. It will be understood that, since a plurality of mooring tendons are required for tethering a tension leg platform, a plurality of mooring tendons are installed either simultaneously or sequentially. As one example, one tendon from each column 30 could be simultaneously installed.
  • the foundation template 36 is pre-installed on the floor 26 of the body of water 22. Location of the foundation template may be by pilings driven into the sea floor terrain or the template 36 may comprise a so-called gravity base which maintains its location principally by means of its sheer size and weight.
  • the template 36 may include one or more pre-drilled well slots which may be completed to tap subsea hydrocarbon formations and then capped off and shut in until connection with the floating TLP structure can be effected.
  • the semi-submersible floating structure 28 is positioned over the foundation template 36.
  • the positioning may be by temporary catenary mooring of the floating structure 28 or, in order to avoid interference by the mooring catenaries in the installation procedure, the floating structure 28 is preferably maintained in position by the use of one or more separate vessels such as tugs and/or crane barges (not shown). It will be understood that the substantially fixed positioning of the floating structure 28 substantially directly vertically over the foundation template 36 is required for the installation procedure.
  • the mooring tendon 46 is pre-constructed as a unitary structure and may be towed to the installation site by a buoyant, off-bottom tow method employing leading and trailing tow vessels 64, 66, respectively.
  • the construction method for the mooring tendons 46 is substantially similar to that described for the construction and transport of subsea flow lines described in U.S. Patent Number 4,363,566 although, other similar methods may be employed.
  • individual short lengths of tubing are welded together to form a unitary structure.
  • the entire length of the tendon is assembled and laid-out on shore prior to its launch as a unitary structure into the water for tow out to the installation site.
  • the mooring tendon 46 is constructed as a thin-walled tubular member so as to be neutrally buoyant in water.
  • flotation means such as buoyancy tanks 68 (Fig. 2a and Fig. 9 in phantom) may be attached to the tendon 46 for the off-bottom tow method.
  • buoyancy tanks 68 Fig. 2a and Fig. 9 in phantom
  • a surface tow method might be utilized.
  • the trailing tow vessel 66 connects a lower control line 78 to the lower tendon coupling section of the mooring tendon 46 and begins to pay out the lower control line 78 allowing the mooring tendon 46 to swing downwardly toward the foundation template 36 (Figs. 2c and 2d).
  • a remote operated vessel (ROV) 80 and its associated control unit 82 are lowered to a point near the foundation template 36.
  • the ROV 80 attaches a pull-in line 84 to the lower end of the mooring tendon 46 on the lower tendon coupling section 54.
  • a diver (not shown) might be utilized to attach the pull in line 84 for applications in more shallow water or the line may be connected before the tendon is swung down.
  • the ROV 80 braces against pull-in guides 86 located adjacent and above the side entry tendon receptacles 42 on the foundation template 36 (Figs. 7a through c).
  • the ROV 80 and the pull-in line 84 act against a restraining force applied on the lower control line 78 to control the entry of the enlarged lower flex connector 62 so that damage to the connector 62 and the receptacle 42 is avoided.
  • a tension force is applied on the upper tendon coupling section 52 through the lead tow line 70 by a tensioning device such as an hydraulic tensioner 88 (Fig. 3), a davit 90 located at the top of each of the cylindrical columns 30 (Fig. 1) or any similar device.
  • a tensioning device such as an hydraulic tensioner 88 (Fig. 3), a davit 90 located at the top of each of the cylindrical columns 30 (Fig. 1) or any similar device.
  • the enlarged upper flex connector 60 is brought into engagement with the side-entry tendon mooring porch 48.
  • the side-entry tendon mooring porch 48 includes a side-entry opening 92 and entry guides 94.
  • the mooring porch 48 also includes a load ring 96 having an upwardly facing bearing surface 98 which is sloped upwardly from its outermost to innermost extent.
  • the upper tendon coupling section 52 incorporates a threaded outer surface 100 to permit length adjustment of the tendon 46.
  • the enlarged upper flex connector 60 includes an adjustment nut 102 having threads which engage the threaded outer surface 100 of the mooring tendon 46. The nut is turned along the threaded coupling section 52 until the effective length of the mooring tendon 46 is somewhat less than the true vertical distance between the floating structure and the anchoring means so that the tendon 46 is in tension. The tensile force on the mooring tendon 46 can thus be adjusted by turning the tendon nut 102 along the threaded outer surface 100 of the upper tendon coupling section 52 to vary the tension loading on the mooring tendon 46.
  • the tendon nut 102 includes an outer surface comprising gear teeth 118 which may be engaged by a gear drive mechanism (not shown) to turn the nut 102 to increase or decrease tendon tension as required.
  • the adjustment nut 102 compressively bears against a flex bearing assembly 104 comprising a face flange 106, an upper connector shroud 108 and an intermediate flex bearing 110.
  • a flex bearing assembly 104 comprising a face flange 106, an upper connector shroud 108 and an intermediate flex bearing 110.
  • the flex bearing 110 generally comprises a typical spherical flex bearing which is common in mooring tendon coupling sections, the flex bearing allowing some angular deviation of the mooring tendon 46 from a strict vertical position thereby allowing compliant lateral movement of the TLP structure.
  • the enlarged lower flex connector 62 of the lower tendon coupling section 54 engages the side-entry receptacle 42 on a lower load ring 120 which substantially corresponds to the load ring 96 of the side-entry tendon mooring porch 48.
  • Side-entry receptacle 42 has a lower frustoconical portion 121 with tapered sides to facilitate insertion of enlarged flex connector 62 into the side-entry receiver 42.
  • Side-entry opening 122 extends laterally at least 1/3 the circumference of lower portion 121 and lengthwise at least twice the maximum dimension of lower flex connector 62.
  • a slanting surface 123 extends between an upper portion of opening 122 and a lower portion of a narrow slot which receives tendon section 54. Surface 123 engages lower tendon section 54 and helps to center it within receptacle 42.
  • the lower load-receiving surface of load ring 120 slopes downwardly from its outermost to its innermost extent.
  • a supplementary surface atop lower back flange 124 mates with the similarly configured surface of load ring 120. The slope on these mating surfaces serves not only to help center connector 62 in receptacle 42 thereby distributing the load but, also, helps close the top and bottom side-entry openings.
  • the load ring 120 is compressively engaged by a lower back flange 124 which is located on the upper portions of a bottom connector shroud 126 of the enlarged lower flex connector 62.
  • the shroud 126 encloses the lower end 128 of the mooring tendon 46 and the lower flex bearing assembly 130 in a cup-like manner.
  • the lower end 128 of the mooring tendon 46 has a frustoconical form having a conical upper surface 132 which engages an inner bearing 134 of the flex bearing assembly.
  • the inner bearing ring 134 is attached to a annular (preferably spherical) flex bearing 136 for translating compressive loadings outwardly to an outer bearing ring 138 which is in engagement with the back flange 124.
  • the flex bearing assembly 130 permits angular deviation of the mooring tendon 46 away from a strictly vertical position.
  • the shroud 126 incorporates a centralizer plug 140 in its base surface.
  • the centralizer plug 140 engages a spherical recess in the lower end 128 of the mooring tendon.
  • tendon 46 may be made of steel and may have an outside diameter of 30" with a 1" wall thickness.
  • Upper and lower tendon coupling sections 52, and 54 may have an OD of about 15" with a wall thickness of 2 1/2".
  • Lower section 54 may be provided with a thin neoprene sleeve to protect it from damage during installation.
  • the central portion of tendon 46 may be of sufficiently larger diameter to provide additional buoyancy to offset the weight of coupling sections 52 and 54.
  • the wall thickness of tendon 46 will, of course, be sufficient to prevent collapse from the water pressure at the maximum depth of utilization and the tendon will be sealed against water entry (i.e., air tight).

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  • Ocean & Marine Engineering (AREA)
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Claims (16)

  1. Tendeur préfabriqué (46) en une seule pièce pour l'amarrage d'une plate-forme (20) à jambes tendues sur le fond (26) de la mer, dans des profondeurs d'eau pouvant atteindre 3000 pieds (= 914,4 m), ledit tendeur (46) étant caractérisé par :
    - une section d'accouplement tubulaire supérieure (52) ayant une première épaisseur et un premier diamètre extérieur de tube ;
    - une section tubulaire centrale (50) qui s'étend sensiblement sur la majeure partie de la longueur dudit tendeur (46), ladite section tubulaire centrale (50) ayant une seconde épaisseur de paroi plus petite que la première épaisseur de paroi et un second diamètre extérieur de tube plus grand que le premier diamètre extérieur de tube, ladite seconde section de paroi ayant une résistance à la traction suffisante pour résister aux forces de compression exercées par ladite mer (22) ;
    - une section d'accouplement tubulaire inférieure (54) ayant une troisième épaisseur de paroi plus forte que la seconde épaisseur de paroi et un troisième diamètre extérieur de tube plus petit que le second diamètre extérieur de tube ; chacune desdites sections tubulaires, supérieure, centrale et inférieure, étant composée de plusieurs segments qui sont soudés pour former un tendeur unitaire ; et
    - des moyens de flottabilité intégrés dans ledit tendeur (46) en une seule pièce de telle manière que ledit tendeur soit d'une flottabilité au moins sensiblement neutre.
  2. Tendeur (46) selon la revendication 1, dans lequel lesdits moyens de flottabilité sont composés desdites sections tubulaires (50, 52, 54) qui sont fermées à joint étanche à l'eau pour maintenir une certaine quantité d'air emprisonnée à l'intérieur, pour fournir la valeur minimum nécessaire de flottabilité.
  3. Tendeur (46) selon la revendication 1 ou 2, dans lequel ladite seconde épaisseur de paroi relativement mince est désignée par "t" et ledit second diamètre de tube relativement grand est désigné par "D", dans lequel ladite épaisseur t et ledit diamètre D satisfont sensiblement la relation
    Figure imgb0011
     où ρt = densité de la matière dont ledit tendeur est fait et ρs = densité de l'eau de mer entourant ledit tendeur.
  4. Procédé d'amarrage d'une plate-forme marine (28) dans une nappe d'eau (22) ayant une surface (24) et un fond (26) comprenant les phases consistant à :
    - préparer plusieurs tendeurs (46) d'une seule pièce, sensiblement rigides, selon une quelconque des revendications précédentes ;
    - placer plusieurs moyens d'ancrage (42) sur le fond (26) de la nappe d'eau (22), les moyens d'ancrage (42) étant adaptés pour recevoir les tendeurs (46) d'amarrage à travers une ouverture d'entrée latérale qui y est prévue ;
    - poster une structure flottante semi-submersible (28) sur la surface (24) de la nappe d'eau (22) au-dessus desdits moyens d'ancrage (42), ladite structure flottante (28) comprenant plusieurs réceptacles extérieurs (48) de tendeurs adaptés pour recevoir, par entrée latérale, lesdits plusieurs tendeurs (46) d'amarrage, lesdits réceptacles (48) de tendeurs étant placés à une distance initiale au-dessus desdits moyens d'ancrage (42) ;
    - disposer lesdits tendeurs (46) sensiblement horizontalement à proximité de ladite surface (24) et dans le voisinage de ladite structure flottante (20), lesdits tendeurs (46) possédant des raccords élargis d'extrémités supérieure et inférieure (60, 62) et une longueur réelle qui est plus grande que ladite distance initiale ;
    - rabattre le raccord élargi (62) d'extrémité inférieure d'un premier desdits tendeurs (46) vers le bas, pour le placer dans une position adjacente à l'un desdits plusieurs moyens d'ancrage (42) ;
    - tirer ledit raccord élargi (62) d'extrémité inférieur de l'un desdits tendeurs (46) à travers ladite ouverture latérale d'un premier desdits moyens d'ancrage (42) ;
    - remonter ledit raccord élargi (62) d'extrémité inférieur pour le mettre en appui contre le moyen d'ancrage (42) ;
    - positionner le raccord élargi (60) d'extrémité supérieure du premier des tendeurs (46) dans un premier desdits réceptacles (48) de tendeur ;
    - régler la longueur effective dudit premier des tendeurs (46) de manière que ladite longueur effective soit plus petite que ladite distance initiale ; et
    - répéter lesdites phases de positionnement, rabattement, traction et réglage pour chacun desdits plusieurs tendeurs (46), de sorte que la plate-forme marine (28) est ainsi amarrée dans la nappe d'eau (22).
  5. Procédé selon la revendication 4, dans lequel ladite phase consistant à poster la structure flottante (22) consiste à poser une rangée de câbles d'amarrage à suspension caténaire entre ladite structure (28) et les ancres placées sur le fond de la nappe d'eau (22).
  6. Procédé selon la revendication 4 ou 5, dans lequel ladite structure flottante (28) possède quatre angles et les phases de positionnement, rabattement, traction et réglage sont simultanément exécutées sur au moins un tendeur (46) adjacent à chacun des angles.
  7. Procédé selon une quelconque des revendications 4 à 6, dans lequel la phase consistant à positionner les tendeurs (46) consiste à remorquer les tendeurs (46) horizontalement à l'aide d'un navire remorqueur de tête (64) amarré à une première extrémité du tendeur (46) et d'un navire remorqueur de queue (66) amarré à l'autre extrémité dudit tendeur (46).
  8. Procédé selon la revendication 7, dans lequel ladite phase de remorquage consiste à remorquer les tendeurs (46) par un procédé de remorquage à flot au-dessus du fond.
  9. Procédé selon la revendication 7, dans lequel ladite phase consistant à rabattre consiste à déhaler un câble de commande (78) de l'un desdits navires remorqueurs (64, 66), ledit câble de commande étant fixé à l'extrémité inférieure du tendeur (46).
  10. Procédé selon une quelconque des revendications 4 à 9, dans lequel ladite phase consistant à tirer l'extrémité inférieure élargie (54) du tendeur (46) à travers l'ouverture latérale des moyens d'ancrage consiste à fixer un câble d'amenée à l'extrémité inférieure élargie (54), le câble d'amenée passant à travers les moyens d'ancrage.
  11. Procédé selon la revendication 10, dans lequel les étapes consistant à fixer un câble d'amenée (78) et à tirer l'extrémité inférieure élargie, utilisent un véhicule submersible.
  12. Procédé selon la revendication 11, dans lequel les phases consistant à fixer ledit câble d'amenée (78) et à tirer l'extrémité inférieure élargie utilise un véhicule submersible (80) commandé à distance.
  13. Procédé selon la revendication 10, dans lequel les phases consistant à fixer ledit câble d'amenée (78) et à tirer l'extrémité inférieure élargie utilisent au moins un plongeur.
  14. Procédé selon une quelconque des revendications 4 à 13, dans lequel ladite extrémité supérieure élargie (60) est filetée et la phase consistant à régler la longueur du tendeur (46) consiste à visser l'extrémité supérieure élargie (60) vers le bas sur les filets.
  15. Procédé selon la revendication 14, dans lequel ladite étape de réglage comprend encore le positionnement de moyens de levage (90) sur la structure flottante (28) au-dessus de l'extrémité élargie (60) du tendeur (46), à fixer les moyens de levage (90) au tendeur (46) et à exercer une tension sur le tendeur (46) à l'aide des moyens de levage (90) en provoquant ainsi l'abaissement de la structure flottante (28) plus profondément dans l'eau (22) et en raccourcissant de cette façon ladite distance initiale.
  16. Procédé selon une quelconque des revendications 4 à 15, dans lequel lesdits plusieurs moyens d'ancrage comprennent un gabarit d'ancrage unique (36) comportant plusieurs réceptacles (42) a entrée latérale, et ladite étape de positionnement consiste à installer le gabarit d'ancrage (36) sur le fond (26) de l'eau.
EP88309317A 1987-10-06 1988-10-06 Appareil d'ancrage et méthode d'installation pour une plate-forme à jambes de tension utilisable en eaux profondes Expired - Lifetime EP0311396B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US07/105,941 US4784529A (en) 1987-10-06 1987-10-06 Mooring apparatus and method of installation for deep water tension leg platform
US105941 1987-10-06
US232396 1988-08-11
US07/232,396 US4848970A (en) 1987-10-06 1988-08-11 Mooring apparatus and method of installation for deep water tension leg platform

Related Child Applications (1)

Application Number Title Priority Date Filing Date
EP91106113.3 Division-Into 1988-10-06

Publications (2)

Publication Number Publication Date
EP0311396A1 EP0311396A1 (fr) 1989-04-12
EP0311396B1 true EP0311396B1 (fr) 1992-07-22

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
EP91106113A Expired - Lifetime EP0441413B1 (fr) 1987-10-06 1988-10-06 Méthode d'installation pour une plate-forme à jambes de tension utilisable en eaux profondes
EP88309317A Expired - Lifetime EP0311396B1 (fr) 1987-10-06 1988-10-06 Appareil d'ancrage et méthode d'installation pour une plate-forme à jambes de tension utilisable en eaux profondes

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP91106113A Expired - Lifetime EP0441413B1 (fr) 1987-10-06 1988-10-06 Méthode d'installation pour une plate-forme à jambes de tension utilisable en eaux profondes

Country Status (8)

Country Link
US (1) US4848970A (fr)
EP (2) EP0441413B1 (fr)
JP (1) JPH01233192A (fr)
KR (1) KR890006928A (fr)
BR (1) BR8805124A (fr)
CA (1) CA1307171C (fr)
DE (2) DE3873013T2 (fr)
DK (1) DK542688A (fr)

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US5117914A (en) * 1990-12-13 1992-06-02 Blandford Joseph W Method and apparatus for production of subsea hydrocarbon formations
US5174687A (en) * 1992-02-14 1992-12-29 Dunlop David N Method and apparatus for installing tethers on a tension leg platform
US5551802A (en) * 1993-02-08 1996-09-03 Sea Engineering Associates, Inc. Tension leg platform and method of installation therefor
US6036404A (en) * 1993-08-31 2000-03-14 Petroleo Brasileiro S.A.-Petrobras Foundation system for tension leg platforms
BR9303646A (pt) 1993-08-31 1995-04-25 Petroleo Brasileiro Sa Sistema de fundação para plataformas de pernas atirantadas
US5984012A (en) * 1998-03-16 1999-11-16 Cooper Cameron Corporation Emergency recovery system for use in a subsea environment
NO315111B1 (no) * 1999-06-07 2003-07-14 Mpu Entpr As Löftefartöy for posisjonering, löfting og håndtering av en marin konstruksjon
US6688814B2 (en) 2001-09-14 2004-02-10 Union Oil Company Of California Adjustable rigid riser connector
US6682266B2 (en) * 2001-12-31 2004-01-27 Abb Anchor Contracting As Tension leg and method for transport, installation and removal of tension legs pipelines and slender bodies
JP2006519138A (ja) * 2003-02-28 2006-08-24 モデク・インターナショナル・エルエルシー テンション・レグ型プラットフォームの設置方法
FR2859495B1 (fr) * 2003-09-09 2005-10-07 Technip France Methode d'installation et de connexion d'une conduite sous-marine montante
US7416025B2 (en) * 2005-08-30 2008-08-26 Kellogg Brown & Root Llc Subsea well communications apparatus and method using variable tension large offset risers
WO2007095197A2 (fr) 2006-02-13 2007-08-23 Kipp Robert M Procédé de verrouillage positif de raccords inférieurs de câble
US8707882B2 (en) 2011-07-01 2014-04-29 Seahorse Equipment Corp Offshore platform with outset columns
US8757082B2 (en) 2011-07-01 2014-06-24 Seahorse Equipment Corp Offshore platform with outset columns
US20130272796A1 (en) * 2011-09-26 2013-10-17 Horton Wison Deepwater, Inc. Modular Relocatable Offshore Support Tower
US9352808B2 (en) 2012-01-16 2016-05-31 Seahorse Equipment Corp Offshore platform having SCR porches mounted on riser keel guide
JP2022545095A (ja) * 2019-08-20 2022-10-25 シングル・ブイ・ムーリングス・インコーポレイテッド テンションレグプラットフォームベースの浮体物を設置するための方法

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Also Published As

Publication number Publication date
US4848970A (en) 1989-07-18
CA1307171C (fr) 1992-09-08
DK542688D0 (da) 1988-09-29
JPH01233192A (ja) 1989-09-18
DE3873013D1 (de) 1992-08-27
EP0441413B1 (fr) 1994-01-12
KR890006928A (ko) 1989-06-16
DE3873013T2 (de) 1992-12-03
EP0311396A1 (fr) 1989-04-12
EP0441413A1 (fr) 1991-08-14
BR8805124A (pt) 1989-05-16
DK542688A (da) 1989-04-07
DE3887173D1 (de) 1994-02-24

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